A distributor for a rotary filter comprising filtration cells rotating in a circular movement is disclosed. Known distributors include:                a fixed collector part comprising at least two compartments, which each have an upward opening in the form of an arc of a circle and at least one liquid discharge pipe, and a central separator chamber, which comprises a downward opening putting the separator chamber in communication with each of the said compartments and a gas outlet pipe, the said downward opening being disposed at a level lower than the said upward opening of each of the compartments,        a movable distributor part which slides over the collector part during the said circular movement and which comprises, per filtration cell, an alveolus having an inlet for receiving a filtered liquid/gas mixture coming from the filtration cell and an outlet which passes opposite the said arc-shaped opening in each of the said compartments during the said circular movement, thus allowing passage of the said mixture in the said collector part, and        means for putting the separator chamber under negative pressure, so as to cause a separation of gas from the liquid/gas mixture flowing in the said compartments of the collector part, with an upward movement of the gas in the separator chamber from its downward opening.        
Such distributors are known and described for example in the patents BE-A-847088 and EP-B-0 175 702.
These devices therefore permit a separation of the gases existing in the liquid/gas mixture forming the separate filtrate in the filtration cells by the arrangement of a central separator chamber into which the gases are drawn.
However, the drawn-in gases entrain with them liquid droplets which must separate by gravity from the gases during the upward movement of the latter which is obtained in the central separator chamber. To do this, the upward speed of the gases at the entry to the separator chamber must preferably be limited in order to increase the efficacy of the separation of the droplets, and therefore the downward opening of the central separator chamber must have a minimum cross section, according to the flow rate of the filtrate reaching the fixed collector part of the distributor.
The drawback of such distributors is that, given this minimum cross section of the central separator chamber, they have an unfavourable overall bulk at the middle of the rotary filter, which results in a greater consumption of friction energy and an additional cost of making the apparatus.